1.3 Sensor Overview & Measurement Parameters

The Solinst Water Level Temperature Sensor is a compact, all-in-one submersible hydrostatic level transmitter that provides continuous, accurate water level and temperature readings for a wide variety of applications.

The durable water level pressure sensor provides 0.05% FS accuracy with automatically temperature compensated readings. There are six pressure ranges to choose from (5-200 m), with options for absolute and vented (gauge) pressure sensor setups.


Water Level Temperature Sensor Specifications
Level Sensor: Piezoresistive Silicon with Hastelloy® sensor (Absolute or Gauge)
Ranges (metres): Absolute: M5, M10, M20, M30, M100, M200
Gauge: M5, M10, M20
Accuracy: ± 0.05% FS
Resolution: 0.0006% FS
Normalization: Automatic Temperature Compensation
Temp. Comp. Range: 0°C to 50°C
Temperature Sensor: Platinum Resistance Temperature Detector (RTD)
Operating Temperature: -20°C to 80°C
Temp. Sensor Accuracy: ± 0.05ºC
Temp. Sensor Resolution: 0.003°C
Response Time: 1~2 minutes
Communication: Digital communications – Modbus and SDI-12
Interface Connector: 4-Conductor
Power Consumption: Max 2mA in idle, 10mA while reading sensor
Size: 22 mm x 192 mm (7/8" x 7.55")
Weight: 173 grams (6.1 ounces)
Wetted Materials: Delrin® , Viton® , 316L stainless steel, Hastelloy, Polyurethane (TPU boot)

Table 1-1 WLTS Technical Specifications



The Model number (e.g. M5) refers to the maximum depth of submergence in meters below water, for that device.


1.3.1 Absolute Level

When submerged, absolute pressure sensors measure total pressure – the pressure of air plus water column above their zero point. The actual pressure of just water above the sensor is obtained by subtracting barometric pressure from the total pressure.


1.3.2 Vented (Gauge) Level

When submerged, vented pressure sensors detect both water and barometric pressure. However, a vent tube to surface allows barometric effects on the pressure sensor to be eliminated. Therefore, they provide readings of the actual pressure of just water above the pressure sensor zero point.


1.3.3 Temperature

The WLTS records temperature compensated water levels. A Platinum Resistance Temperature Detector is used to accurately compensate for temperature changes within the range of 0ºC to +50ºC.